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Subject[PATCH] cpufreq: add imx8mq-cpufreq driver
Date
Add imx8mq-cpufreq driver for NXP i.MX8MQ SoC to support the
hardware specific frequency and voltage scaling requirements.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
drivers/cpufreq/Kconfig.arm | 8 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/imx8mq-cpufreq.c | 234 +++++++++++++++++++++++++++++++++++++++
3 files changed, 243 insertions(+)
create mode 100644 drivers/cpufreq/imx8mq-cpufreq.c

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 96b35b8..ea8e2b6 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -105,6 +105,14 @@ config ARM_IMX6Q_CPUFREQ

If in doubt, say N.

+config ARM_IMX8MQ_CPUFREQ
+ tristate "NXP i.MX8MQ cpufreq support"
+ select PM_OPP
+ help
+ This adds cpufreq driver support for NXP i.MX8MQ SoC.
+
+ If in doubt, say N.
+
config ARM_KIRKWOOD_CPUFREQ
def_bool MACH_KIRKWOOD
help
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 8d24ade..a3bc61c 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_ARCH_DAVINCI) += davinci-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS5440_CPUFREQ) += exynos5440-cpufreq.o
obj-$(CONFIG_ARM_HIGHBANK_CPUFREQ) += highbank-cpufreq.o
obj-$(CONFIG_ARM_IMX6Q_CPUFREQ) += imx6q-cpufreq.o
+obj-$(CONFIG_ARM_IMX8MQ_CPUFREQ) += imx8mq-cpufreq.o
obj-$(CONFIG_ARM_KIRKWOOD_CPUFREQ) += kirkwood-cpufreq.o
obj-$(CONFIG_ARM_MEDIATEK_CPUFREQ) += mediatek-cpufreq.o
obj-$(CONFIG_MACH_MVEBU_V7) += mvebu-cpufreq.o
diff --git a/drivers/cpufreq/imx8mq-cpufreq.c b/drivers/cpufreq/imx8mq-cpufreq.c
new file mode 100644
index 0000000..2aee6049
--- /dev/null
+++ b/drivers/cpufreq/imx8mq-cpufreq.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 NXP
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/cpu_cooling.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+
+static struct device *cpu_dev;
+static bool free_opp;
+static struct cpufreq_frequency_table *freq_table;
+static unsigned int transition_latency;
+static struct thermal_cooling_device *cdev;
+static struct regulator *arm_reg;
+static unsigned int max_freq;
+
+#define IMX8MQ_CPUFREQ_CLK_NUM 5
+
+enum IMX8MQ_CPUFREQ_CLKS {
+ A53,
+ A53_SRC,
+ ARM_PLL,
+ ARM_PLL_OUT,
+ SYS1_PLL_800M,
+};
+
+static struct clk_bulk_data clks[] = {
+ { .id = "a53" },
+ { .id = "a53_src" },
+ { .id = "arm_pll" },
+ { .id = "arm_pll_out" },
+ { .id = "sys1_pll_800m" },
+};
+
+static int imx8mq_set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ struct dev_pm_opp *opp;
+ unsigned long freq_hz, volt;
+ unsigned int old_freq, new_freq;
+ int ret;
+
+ new_freq = freq_table[index].frequency;
+ freq_hz = new_freq * 1000;
+ old_freq = policy->cur;
+
+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
+ if (IS_ERR(opp)) {
+ dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
+ return PTR_ERR(opp);
+ }
+ volt = dev_pm_opp_get_voltage(opp);
+ dev_pm_opp_put(opp);
+
+ dev_dbg(cpu_dev, "%u MHz --> %u MHz\n",
+ old_freq / 1000, new_freq / 1000);
+
+ if (new_freq > old_freq) {
+ ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale arm_reg up: %d\n",
+ ret);
+ return ret;
+ }
+ }
+
+ clk_set_parent(clks[A53_SRC].clk, clks[SYS1_PLL_800M].clk);
+ clk_set_rate(clks[ARM_PLL].clk, new_freq * 1000);
+ clk_set_parent(clks[A53_SRC].clk, clks[ARM_PLL_OUT].clk);
+
+ /* Ensure the arm clock divider is what we expect */
+ ret = clk_set_rate(clks[A53].clk, new_freq * 1000);
+ if (ret)
+ dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+
+ if (new_freq < old_freq) {
+ ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale arm_reg down: %d\n",
+ ret);
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+static void imx8mq_cpufreq_ready(struct cpufreq_policy *policy)
+{
+ cdev = of_cpufreq_cooling_register(policy);
+}
+
+static int imx8mq_cpufreq_init(struct cpufreq_policy *policy)
+{
+ int ret;
+
+ policy->clk = clks[A53].clk;
+ ret = cpufreq_generic_init(policy, freq_table, transition_latency);
+ policy->suspend_freq = max_freq;
+
+ return ret;
+}
+
+static struct cpufreq_driver imx8mq_cpufreq_driver = {
+ .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = imx8mq_set_target,
+ .get = cpufreq_generic_get,
+ .init = imx8mq_cpufreq_init,
+ .name = "imx8mq-cpufreq",
+ .ready = imx8mq_cpufreq_ready,
+ .attr = cpufreq_generic_attr,
+ .suspend = cpufreq_generic_suspend,
+};
+
+static int imx8mq_cpufreq_probe(struct platform_device *pdev)
+{
+ struct device_node *np;
+ int ret, num;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev) {
+ pr_err("failed to get cpu0 device\n");
+ return -ENODEV;
+ }
+
+ np = of_node_get(cpu_dev->of_node);
+ if (!np) {
+ dev_err(cpu_dev, "failed to find cpu0 node\n");
+ return -ENOENT;
+ }
+
+ ret = clk_bulk_get(cpu_dev, IMX8MQ_CPUFREQ_CLK_NUM, clks);
+ if (ret)
+ goto put_node;
+
+ arm_reg = regulator_get(cpu_dev, "arm");
+ if (PTR_ERR(arm_reg) == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ dev_dbg(cpu_dev, "regulator not ready, defer\n");
+ goto put_reg;
+ }
+ if (IS_ERR(arm_reg)) {
+ dev_err(cpu_dev, "failed to get regulator\n");
+ ret = -ENOENT;
+ goto put_reg;
+ }
+
+ /*
+ * We expect an OPP table supplied by platform.
+ * Just, in case the platform did not supply the OPP
+ * table, it will try to get it.
+ */
+ num = dev_pm_opp_get_opp_count(cpu_dev);
+ if (num < 0) {
+ ret = dev_pm_opp_of_add_table(cpu_dev);
+ if (ret < 0) {
+ dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
+ goto put_clk;
+ }
+ }
+ free_opp = true;
+
+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+ if (ret) {
+ dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
+ goto out_free_opp;
+ }
+ max_freq = freq_table[--num].frequency;
+
+ if (of_property_read_u32(np, "clock-latency", &transition_latency))
+ transition_latency = CPUFREQ_ETERNAL;
+
+ ret = cpufreq_register_driver(&imx8mq_cpufreq_driver);
+ if (ret) {
+ dev_err(cpu_dev, "failed register driver: %d\n", ret);
+ goto free_freq_table;
+ }
+
+ of_node_put(np);
+ return 0;
+
+free_freq_table:
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_free_opp:
+ dev_pm_opp_of_remove_table(cpu_dev);
+put_clk:
+ clk_bulk_put(IMX8MQ_CPUFREQ_CLK_NUM, clks);
+put_reg:
+ if (!IS_ERR(arm_reg))
+ regulator_put(arm_reg);
+put_node:
+ of_node_put(np);
+ return ret;
+}
+
+static int imx8mq_cpufreq_remove(struct platform_device *pdev)
+{
+ cpufreq_cooling_unregister(cdev);
+ cpufreq_unregister_driver(&imx8mq_cpufreq_driver);
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+ if (free_opp)
+ dev_pm_opp_of_remove_table(cpu_dev);
+ regulator_put(arm_reg);
+ clk_bulk_put(IMX8MQ_CPUFREQ_CLK_NUM, clks);
+
+ return 0;
+}
+
+static struct platform_driver imx8mq_cpufreq_platdrv = {
+ .driver = {
+ .name = "imx8mq-cpufreq",
+ },
+ .probe = imx8mq_cpufreq_probe,
+ .remove = imx8mq_cpufreq_remove,
+};
+module_platform_driver(imx8mq_cpufreq_platdrv);
+
+MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
+MODULE_DESCRIPTION("Freescale i.MX8MQ cpufreq driver");
+MODULE_LICENSE("GPL");
--
2.7.4
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